Traditionally, LGBs are used to guide conventional general-purpose, multi-effect or penetrator warheads against point surface or sub-surface targets. The impact of the warhead with the target or ground initiates the fuze installed in the warhead, causing instantaneous or delayed detonation of the warhead depending on the fuze setting.
There are limitations with the traditional method of employing LGBs. While extremely effective against stationary point surface or sub-surface targets such as stationary vehicles, large ships, buildings, shelters or bunkers, it is less effective against fast moving vehicles, smaller, more maneuverable watercraft or area targets such as troops entrenched or in an open field. This is due, in part, to the degradation of accuracy of the weapon against moving targets combined with a significant portion of the blast and fragmentation of the warhead being absorbed by the ground at impact, effectively reducing the probability of disabling or destroying the intended target. This, then necessitates that the pilot or aircrew either reattack the target or to carry a mix of different weapons to address multiple types of targets. Neither situation is optimal in a theater of operations, where reducing exposure to hostile fire is vital to aircrew and aircraft survivability. Thus, it would be desirable to provide a system that enables the LGB to detonate the warhead prior to impact with the ground, in order to maximize the blast and fragmentation effects of the warhead against these types of targets without requiring modification of the guidance and control section hardware and/or software/firmware of the LGB itself.
No conventional system provides both laser guidance and airburst capability for a dumb-bomb, while also avoiding the use of complex Inertial Navigation System (INS) and Global Positioning System (GPS) guidance systems. For example, Paveway II is a conventional bolt-on kit for converting an unguided bomb (e.g., a dumb-bomb) to a LGB. While Paveway II provides laser guidance, it does not have airburst capability.
More specifically, Paveway II kits attach to a variety of warheads, and include a computer control group (CCG) containing a laser detector (e.g., a semi-active laser (SAL) seeker), a computer section containing guidance and control electronics, thermal battery, and a control actuation system (CAS). There are moveable front control canards and fixed rear wings for stability. The weapon guides on reflected laser energy: the seeker detects the reflected light (“sparkle”) of the designating laser, and actuates the canards to guide the bomb toward the designated point. Paveway II uses only laser guidance for guiding the bomb, and does not utilize INS/GPS guidance. Paveway II also does not include a data interface to the launch platform. For example, since Paveway II does not utilize GPS, there is no need for Paveway II-equipped munitions to receive any position data, velocity vectors, and target coordinates from the aircraft.
Enhanced Paveway II and Paveway IV (later versions of Paveway) are dual mode INS/GPS and laser-guided bomb kits that are based on an Enhanced Computer Control Group (ECCG). The newer ECCG in Enhanced Paveway II and Paveway IV can contain a Height of Burst (HOB) sensor enabling air burst fuzing options, and a SAASM (Selective Availability Anti Spoofing Module) compliant GPS receiver. As such, Enanced Paveway II and Paveway IV provide both laser guidance and airburst capability, but with the drawback of increased cost and complexity due to the ECCG and INS/GPS guidance.
The Joint Direct Attack Munition (JDAM) is another conventional bolt-on guidance kit, that converts unguided munitions (i.e., dumb bombs) into guided munitions. By adding a tail section containing INS/GPS guidance to existing munitions, JDAM provides highly accurate delivery in any flyable weather. Guidance is provided by a JDAM through a tail control system and INS/GPS system. The INS, using updates from the GPS, guides the bomb to the target via the use of movable tail fins. The navigation system is initialized by transfer alignment from the aircraft that provides position and velocity vectors from the aircraft systems. Once released from the aircraft, the JDAM autonomously navigates to the designated target coordinates. Target coordinates can be loaded into the aircraft before takeoff, manually altered by the aircrew in flight prior to weapon release, or entered by a datalink from onboard targeting equipment.
A basic JDAM tail kit does not include laser guidance or airburst. However, these capabilities can be added to a JDAM with additional components. For example, a Laser JDAM (LJDAM) adds a laser seeker to the nose of a JDAM-equipped warhead, giving the ability to engage moving targets to the JDAM. The laser seeker is called Precision Laser Guidance Set (PLGS) and consists of the laser seeker itself, known as a DSU-38, installed on the nose of the warhead and a wire harness fixed under the warhead body to connect the DSU-38 with the JDAM tail kit. Another upgrade to the basic JDAM system is a DSU-33, which is a radar proximity sensor that provides a HOB fire pulse signal to the fuze for JDAM-equipped warheads. The DSU-33, like the DSU-38, is designed to be installed in the nose well of a warhead. As such, a JDAM-equipped warhead can only be equipped with one, but not both, of a DSU-33 and a DSU-38.
The DSU-38 is specifically designed to operate with the JDAM kit and is not compatible with a Paveway II kit. The DSU-33 can be used on a warhead without a Paveway II kit to provide airburst capability to an unguided bomb. However, the DSU-33 cannot be used on a warhead that is equipped with a Paveway II kit. This is because a DSU-33 and the guidance kit for Paveway II both occupy the same place on the warhead such that attaching one to a warhead means that you cannot attach the other to the same warhead.